[1]
S. Kochmanski, “On the evolution operators for some equations of mathematical physics with variable coefficients”, Ukr. Mat. Zhurn., vol. 46, no. 7, pp. 857–869, Jul. 1994, Accessed: Dec. 06, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/5677